Languages

The Cities Of The 21st Century Will Be Defined By Water

“If we only respond to the past, we will only get answers that fit the past,” says Dutch water expert Henk Ovink.

Rives Taylor, a principal at the architecture firm Gensler and a 40-plus-year resident of Houston, is lucky.

His home in Houston Heights, an older neighborhood northwest of downtown, was spared from Hurricane Harvey’s flooding. Part of that is due to the natural topography of the area–its elevation is few feet higher than downtown–and that his pier-and-beam house is three feet off the ground. But what’s also remarkable about his neighborhood is that it isn’t connected to the city’s vast network of underground storm sewers. Rainwater flows directly into nearby ditches where it eventually seeps back into the earth.

This type of flood management strategy more closely mimics the natural water cycle–an approach called “low-impact development.” Also known as “green infrastructure,” it means designing systems that allow urban runoff to naturally infiltrate the soil instead of channeling it into pipes and storm drains. This strategy isn’t new, but it’s still viewed as “alternative” to the way most cities were designed in the 19th and 20th centuries.

“Passive approaches [to flood management] are always the key,” Taylor says of low-impact development. “You can’t always have people putting in flood walls and pump systems–it has to be smart without an expert involvement. Our challenge is being passively smart.”

Now, as cities wrestle with the reality of more intense storms, more flooding, and more water to manage, low-impact development is earning renewed recognition as an essential mechanism to help them become more resilient. It’s emblematic of a broader philosophical shift in how architects, engineers, and planners think about water: as a resource to live with, instead of pushing away. And as Houston begins to recover, experts are pushing for the city–and others–to adopt the same ethos.

A NEW, AGGRESSIVELY PASSIVE APPROACH TO WATER

A typical stormwater system is built to do two things: capture runoff into underground pipes and sewers that channel it as far and fast away from streets and buildings as possible, and discharge that runoff into a larger body of water. This highly engineered system causes a number of environmental problems: Large volumes of water can overpower the system, the runoff collects pollutants, and water that normally would recharge groundwater resources can’t reach aquifers, leading to subsidence. Plus, as water travels it picks up speed and causes erosion.

Keeping rainwater close to the site where it lands helps alleviate these pressures on stormwater infrastructure, which ultimately makes it more resilient. A few of the tools in the green infrastructure kit? Infiltration ponds, rain gardens, bioswales, permeable pavement, open space, and green roofs. The more of these natural systems cities adopt, the less they have to rely on heavy engineering, which can fail, requires maintenance and constant upkeep, and is expensive to operate. What’s more, traditional infrastructure was built to specifications that are now in flux, as climate change makes rainfall and storms less predictable.

Houston is a perfect example of this dichotomy. With mile after mile of sprawl and the hard surfaces that come along with it–roads, driveways, parking lots, freeways–the city’s urban design contributes to its frequent flooding. All of the rain that falls on Houston’s 630-square-mile area flows through the city’s bayou system to Galveston Bay. After Hurricanes Allison and Ike, the city began to adopt more green infrastructure to help reduce the risk of flooding at a variety of scales.

For instance, a master plan will improve Buffalo Bayou–one of the main waterways in the city–by restoring its natural ecosystems (enhancing recreation opportunities nearby, too). The city is transforming some of its traffic lanes into bioswales, which are landscaping elements designed to collect stormwater and let it slowly percolate back into the earth. The landscape architecture firm West 8 is designing the forthcoming Houston Botanic Garden to include floodable forests, wetland gardens, and topographies elevated above the flood line to help it withstand extreme weather.

But as a whole, the city still adheres to the old way of managing water and hasn’t been as aggressive as it could be with adopting new water management policies. “It’s not nearly as extensive as it could be,” Taylor says. “We’re in transition . . . It takes years of activity at the regional scale to make change.”

Improving permeability is the key to resilience. “I always think about cities like people, or bodies,” says Claire Weisz, a founding principal of WXY, a New York architecture and urban design firm that is heavily involved in Hurricane Sandy reconstruction efforts, like rebuilding Rockaway Beach. “It’s as if Houston isn’t using the largest organ humans have, which is the skin, to help itself.”

It’s not just Houston that could benefit from this type of approach, according to Laura Tam, the sustainable development policy director at SPUR, an urbanism think tank based in San Francisco.

“With climate change, larger and bigger storms are more frequently harming urban areas, especially along the coast, she says. “Rather than assuming an engineered approach to flooding, we’re staring to think about an approach that lets us live with water on the landscape, to harvest it and to manage it though contouring the land differently. Those are some of the tools we’ll have to put back into areas built without future flooding in mind.”

Now, cities face an urgent challenge to introduce more green infrastructure as they’re inundated. And some are turning to the world’s foremost experts on flooding for help.

HELP FROM THE NETHERLANDS

The Dutch are regarded as experts in the field of water management, a necessity as their country developed around a river delta and coastline–very prosperous in terms of trade and framing, but also highly vulnerable to flooding. Even before the Netherlands established a formal governance system, it had a regional water authority that ensured that flood management was a priority and understood that it must be a flexible and constantly evolving approach.

“We built this culture of living with water,” says Henk Ovink, the Netherlands’ special envoy for international water affairs. Ovink’s position was developed to help other countries adopt the Dutch approach to managing water, an increasing necessity elsewhere in the world.

For instance, Ovink worked very closely with the Hurricane Sandy relief efforts and helped launch Rebuild by Design, a federally funded competition to spark forward-thinking infrastructure investment and water management strategies in the tri-state area. He’s also helping the New York-New Jersey-Connecticut metropolitan area with its next regional plan, which only occurs every 40 years or so. He believes that cities must change the way they think about water, and accept that our relationship with it in the future is uncertain.

“If we only respond to the past, we will only get answers that fit the past,” he says. “Those answers won’t fix the future . . . You really have to look at the city from a whole new perspective.”

While the Dutch pioneered heavy-duty infrastructure like dikes, sea walls, sea gates, and levees to hold back water, in the 1990s they realized that this approach was futile. The natural ecological systems would eventually overtake the man-made. Instead, they adopted a strategy they nicknamed “Making Room for the River,” which means giving the rivers and waterways room to breathe. This required giving more space to the rivers so they could meander and swell naturally and take on extra water during storms. But these areas were also turned into parks and public amenities for all the other days when flooding isn’t an issue.

The same ideas are now pertinent in the U.S., from Houston to the Northeast. New York is adopting this approach with its forthcoming network of waterfront parks that also function as a storm-surge buffer. “Engineering alone won’t bring you salvation,” Ovink says. Stormwater management and flood resiliency are not particularly sexy topics, but integrating them into desirable new public spaces and recreation areas could hasten more green infrastructure in Houston and elsewhere.

“It has many more co-benefits versus a grayer alternative and that includes things like better streets, better pedestrian environments, more habitat, trees provide cooling, when you have the opposite problem of a big flood,” SPUR’s Laura Tam says. “You don’t have to believe in climate change to see that it’s preferable. You can get people on board through the project itself in its own right.”

EMBRACING A CULTURE OF WATER

While Houston is doing this already with Buffalo Bayou, the flooding problems aren’t just in the city itself–it’s a challenge from the local to the regional to the state and even the federal level, considering the myriad jurisdictions involved with infrastructure. The difficulty will be galvanizing both public and private entities to embrace a culture of water, and that means long-term flood planning at all scales. “Macro- and micro-scale thinking is the key,” Gensler’s Rives Taylor says. “It’s not new; we need to be clever to make sure it happens.”

What will get this process moving? It could be a Rebuild by Design-type activation, which brings together multiple jurisdictions, designers, engineers, and investors, and helps ensure that any idea that moves forward is driven by diverse perspectives, not just a single vision that’s imposed on an area.

“[New York, New Jersey, and Connecticut] really benefited from a federal competition saying we can’t answer this by just building a wall–it has to be more than just a barrier,” WXY’s Claire Weisz says. “Keeping water out at the cost of quality of life of the city isn’t a choice. That’s really the big change from the 1950s-style infrastructure we’re all living with. The hope is that Houston and Texas will look at [Rebuild] and say, ‘How do we want to do this our way? How do we want to do this in a way that reflects our talents and attitudes?'”

To Otto Condon–an urban design principal in the architecture firm ZGF’s Washington, D.C., office–catalyzing more green infrastructure requires what he calls “twofers and threefers.” In other words, being able to tell multiple stories to different audiences about why investing in this type of project makes sense.

“It’s the architect’s responsibility to speak holistically,” he says. “We can’t just speak about beauty and amenity; it has to be about equity, social justice, economics, and a good return on investment. You need to bring the metrics.”

He points out that the success of green infrastructure in D.C. is due to one of its policies: Development projects can trade stormwater credits in a similar way that carbon emission are traded. Projects that exceed the baseline can then sell their credits and earn money.

While increasing regulation is always a touchy topic, laws could incentivize the cultural shift around water that vulnerable cities need. For example, Tam suggests controls on sprawl to prevent further development in risky flood zones. “Rules can be carrots and sticks,” Weisz says. “In a way Houston needs a lot of carrots at this point to make things happen.”

THE DIRE RISK OF POLITICAL GRIDLOCK

If cities don’t adopt a more progressive approach to water management, the consequences are cut and dry. “We build to fail,” Ovik says. “We lose more lives and dollars in the near future. I don’t have to be a fortune teller to see that; we already see it all over the world.” (This summer alone, floods in south Asia have killed over 1,000 people.)

Houston has had no shortage of designers and planners calling for a regional infrastructure plan, like the Ike Dike. The challenge has been establishing financial responsibility and getting the dozens of stakeholders (and millions of residents) on board with a plan, which has led to the region’s sluggishness in updating its approach to infrastructure.

“I hope this has been a good instructive lesson for national and state leaders who have tended not to want to spend money locally and for the local leaders who haven’t been aggressive with the money they do have,” Taylor says. “I’m hoping that in terms of infrastructure–roadways, waterways, and the Flint, Michigans of the country–we would take any expenditure and think about a lifecycle.”

Ovik prefers to take a positive perspective and is eager to lend his expertise and help any way possible–a sentiment echoed in all the architects I spoke with for this story. Design–or a lack thereof–got Houston into the predicament it’s in today. Perhaps it can help make it more resilient.

“We live in dangerous times but we can use that as an opportunity to change,” he says. “I’m hopeful. I’m an optimistic man. We can tip the scales–we just have to have the guts to do it.

This article is culled from daily press coverage from around the world. It is posted on the Urban Gateway by way of keeping all users informed about matters of interest. The opinion expressed in this article is that of the author and in no way reflects the opinion of UN-Habitat.